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Abstract: Four new organotin(IV) compounds [Me3SnL] (1), {[Me2SnL]2O}2 (2), Bu2SnL2 (3) and [Bu3SnL] (4), where L = O2C(C2H5)CCHC6H4F have been synthesized by refluxing the corresponding organotin(IV) chlorides with sodium (E)-2-(2-fluorobenzylidene) butanoate (NaL) in dry toluene except 2 for which Me2SnO was refluxed with (E)-2-(2-fluorobenzylidene) butanoic acid (LH) in the same solvent. NaL and all the compounds were characterized by FT-IR, 1H NMR and 13C NMR spectroscopy. NaL and compounds 1 and 2 were also characterized by X-ray single crystal analysis which confirmed a linear polymeric structure for compound 1 and a stannoxane for 2. The structural analyses have shown a bridging behavior of the ligand in trimethyl- and tributyl-, chelating as well as bridging behavior in dimethyl- and a chelating bidentate mode of coordination in dibutyltin(IV) compound which is also confirmed from the crystal analysis for compounds 1 and 2. Cyclic voltammetry was used to evaluate the electrochemical, kinetic and thermodynamic parameters for the electron transfer processes of compounds 1–4. Predominantly adsorption controlled redox processes were exhibited by the slope of log i p vs. −log v plots. The values of the diffusion coefficient (D o) indicated the role of solvent in the mobility of the electro-active species to some extent but the overall rate of the redox process was typical of the adsorption controlled process and could not be explained on the basis of solvation effects. The values of formal potential and charge transfer coefficient were also calculated. [Copyright &y& Elsevier]

Abstract: Chloro-diorganotin(IV) complexes of 4-methyl-1-piperidine carbodithioic acid (4-MePCDTA) have been synthesized by the reaction with diorganotin dichloride in 1:1 molar ratio in anhydrous toluene. These newly synthesized complexes have been characterized by elemental, IR, multinuclear NMR (1H and 13C) and mass spectrometric studies. The crystal structures of complex 1 [Me2SnCl(4-MePCDT)] and 3 [Ph2SnCl(4-MePCDT)] have been determined by X-ray single crystal analysis, which show trigonal bipyramid geometry. These complexes were tested for their antimicrobial activity against six different plant and human pathogens. The screening results show that the complexes exhibit higher antibacterial and antifungal activity than the free ligand. [Copyright &y& Elsevier]

A series of organotin(IV) derivatives R 3 SnL ( 1–3 ), R 2 SnLCl ( 4–6 ) and R 2 SnL 2 ( 7–9 ) (where R = Me, Bu, Ph and L = 4-(benzo[d][1,3]dioxol-5-ylmethyl)piperazine-1-carbodithioate) were prepared from the reaction of 4-(benzo[d][1,3]dioxol-5-ylmethyl)piperazine-1-carbodithioate (L-salt) with the corresponding triorganotin(IV) chlorides and diorganotin(IV) dichlorides. All compounds were characterized by FT-IR, 1 H, 13 C and 119 Sn NMR spectroscopy. Dimethylstannyl bis(4-(benzo[d][1,3]dioxol-5-ylmethyl)piperazine-1-carbodithioate) ( 7 ) was also characterized in the solid state by single crystal x-ray diffraction, showing a distorted octahedral geometry. The diorganotin(IV) derivatives have shown significant antibacterial and antifungal activity and good cytotoxic activity against ovarian cancer cells with IC 50 values greater or comparable to that of cisplatin . [ABSTRACT FROM AUTHOR]

Biodiesel fuel has shown great promise as an alternative to petro-diesel fuel. Biodiesel production is widely conducted through transesterification reaction, catalyzed by homogeneous catalysts or heterogeneous catalysts. Fourteen new organotin(IV) carboxylate complexes were preliminary screened for their catalytic activity in transesterification. The transesterification reaction, which is a major path to produce biodiesel, occurs between the triglyceride vegetable oils with alcohols to form esters (biodiesel) and glycerol. The present investigation involves the production of environmental-friendly heterogeneous catalyst, organotin(IV) carboxylates, for biodiesel production from corn oil. 83% Conversion of corn oil into biodiesel was obtained in the presence of the synthesized catalysts. Therefore, the newly synthesized organotin(IV) carboxylate complexes can be used as one of the best catalysts in future for the biodiesel synthesis. [ABSTRACT FROM AUTHOR]

Abstract: A series of five monomeric and polymeric complexes: [Bu3Sn(C5H4O2S)] (1), [Me3Sn(C5H4O2S)] (2), [Cy3Sn(C5H4O2S)] (3), [Bu2Sn(C5H4O2S)2] (4), [Oct2Sn(C5H4O2S)2] (5) of thiophene-2-carboxylic acid have been synthesized by the reaction of ligand acid with di- organotin compounds for the complexes 4, 5 and its sodium salt with tri-organotin compounds for the complexes 1, 2 and 3 respectively, in suitable stoichiometries. All complexes have been structurally characterized by vibrational and magnetic resonance (1H, 13C NMR) spectroscopies. The structures of complexes (2), (3) and (4) have also been elucidated by X-ray crystallography. Relative potential has been assessed for their anti-bacterial, DNA protection and inhibitory assay against acetyl cholinesterase and butyryl cholinesterase. [Copyright &y& Elsevier]

Abstract: Nine organotin esters, Me2SnL2 1, Me3SnL 2, n-Bu2SnL2 3, n-Bu3SnL 4, Ph3SnL 5, (PhCH2)2SnL2 6, [(Me2SnL)2O]2 7, Et2SnL2 8 and n-Oct2SnL2 9, of (E)-3-(3-fluorophenyl)-2-(4-chlorophenyl)-2-propenoic acid, HL have been synthesized and characterized by elemental analysis, IR, Multinuclear NMR (1H, 13C and 119Sn) and mass spectrometry. The geometry around the tin atom has been deduced and compared both in solution and solid states. The crystal structure of compound 5 has been determined by X-ray single crystal analysis, which shows a tetrahedral geometry around the tin atom with space group . These compounds have also been screened for bactericidal, fungicidal activities and cytotoxicity data. [Copyright &y& Elsevier]

The reactions of (E)-2-chloro(dimethyl)stannyl-3-diethylboryl-N,N-dimethyl-2-pentenylamine 2, containing penta-coordinate tin, with lithium diethylamide, -diiso-propylamide, -bis(trimethylsilyl)amide, with N-lithiated azoles (pyrrole, 1,2,4-triazole), and C-lithiated azoles (N-methylimidazole, thiazole and 4-methylthiazole) were studied. Most of the products 3–11 correspond closely to those obtained previously from (E)-2-chloro(dimethyl)stannyl-3-diethylboryl-2-pentene 1. However, there is a tendency for the increase in the coordination number of tin in the 1,2,5-azoniastannaboratole derivative 3, the 1,3-stannaborole derivative 4, the bis(trimethylsilyl)amide 5 and the N-pyrrolylborane 6. In the products derived from 1,2,4-triazole (7), N-methylimidazole (8), thiazole (9, 10) and 4-methyl-thiazole (11), the coordinative N–Sn bonding with the dimethylamino group is strong, as indicated by multinuclear magnetic resonance data in solution (1H-, 11B-, 13C-, 14/15N-, 119Sn-NMR), and by X-ray structural analysis of 11 in the solid state. In the cases of 10 and 11, zwitterionic structures are formed, in which tin is linked to nitrogen, and boron to carbon of the thiazole. These compounds can be classified as carbene–borane adducts. [Copyright &y& Elsevier]

Triallylborane reacts with most poly-1-alkynylsilanes (1–5), containing up to four C&z.tbnd6;C units, or di(1-alkynyl)tin compounds (6) to give either siloles (8, 11, 14, 16), as the result of an intermolecular 1,1-allylboration followed by an intramolecular 1,1-vinylboration, or the novel 2-alkylidene-1,3-silaborolene (9) or 2-alkylidene1,3-stannaborolene derivatives (17), as the result of intermolecular 1,1-allylboration followed by an intramolecular 1,2-allylboration. In the case of the borolene derivatives, a second intramolecular 1,2-allylboration takes place to give 1,7-borasila- or 1,7-borastannabicyclo[4.3.0]nona-5,8-diene derivatives (10, 12, 13, 15, 18). If the starting materials are di(1-alkynyl)methylsilicon hydrides (2), the latter reaction affords selectively only one diastereomer (10(H)). All products were characterised by extensive multinuclear magnetic resonance spectra (1H-, 11B-, 13C-, 29Si-, and 119Sn-NMR). [Copyright &y& Elsevier]

Abstract: This article describes the synthesis of four new homobimetallic organotin(IV) complexes: [Et2Sn]2L (1), [Bu2Sn]2L (2), [Oct2Sn]2L (3) and [BuClSn]2L (4) (H 4 L = N 1′,N 6′-bis(5-bromo-2-hydroxybenzylidene)adipodihydrazide) and their structural elucidation by means of elemental analysis, mass spectroscopy, FT-IR, NMR (1H, 13C, 119Sn) and single crystal X-ray analysis. Spectroscopic studies indicate coordination of hexadentate ligand to the diorganotin(IV) moieties via ONO–ONO donor sites and pentacoordinated tin centers. Single crystal X-ray analysis of (1) and (2) revealed homobimetallic nature of complexes with each Sn atom in a distorted square pyramidal coordination geometry. Packing diagrams suggest the seminal role of Sn⋯N and Br⋯π interactions in generating supramolecular assembly. The synthesized compounds were screened for their antimicrobial activity and cytotoxicity. Compound (2) exhibit highest activity against several pathogenic microbes. [Copyright &y& Elsevier]

Abstract: This article describes the synthesis, characterization and bioactivity of dimethyl (1), diethyl (2), diphenyl (3), di-n-octyl (4), di-tert-butyl (5), n-butylchlorotin(IV) (6) derivatives of N′-(2-hydroxy-3-methoxybenzylidene)formohydrazide ligand. On the basis of presence or absence of steric factor, these compounds are either mononuclear in which Sn atom is in distorted trigonal bipyramidal geometry (3) or homobimetallic with each Sn atom in pentagonal bipyramidal environment (1). Packing diagrams suggest that the H⋯N, H⋯π and π⋯π interactions play a seminal role in generating fascinating supramolecular structures. These complexes show good antileishmanial, antiurease, antibacterial and antifungal activities. Moreover, the antileishmanial activity of 3 and 5 is comparable with standard antileishmanial drug Amphotericin B. [Copyright &y& Elsevier]

A series of organotin(IV) carboxylate complexes [Me2SnL2] (1), [Bu2SnL2] (2), [Oct2SnL2] (3), [Me3SnL] (4), [Bu3SnL] (5) and [Ph3SnL] (6), where L = O2C(CH3)C＝CHC6H4F have been successfully synthesized and characterized by FT-IR, NMR (1H, 13C) and single crystal analysis. The ligand coordinates to tin atom via carboxylate group. Compound 1 and 4 have also been studied by single crystal XRD analysis. The synthesized compounds were screened for their biological activities including anti-bacterial, anti-fungal, anti-tumor and cytotoxicity. The compounds 4–6 exhibit excellent anti-bacterial, anti-fungal and anti-tumor activities. The ligand binds with DNA double helix by hydrogen bonding between the ligand and the base pairs in DNA typically to N3 of adenine and O2 of thymine as well as partial intercalation of aromatic ring into the base pairs of DNA. The complexes also interact with DNA via intercalation of aromatic ring into the base pairs of DNA. The catalytic activity of compounds 46 was assessed in transesterification of triglycerides in rocket seed oil into biodiesel. The choice of these compounds is the Lewis acid nature of tin atom. The samples were taken in regular interval of 1, 8, 16 and 24 h and % age conversion was determined by 1H NMR. All the tested compounds showed good catalytic activity in the order 4 > 5 > 6. [Copyright &y& Elsevier]

Abstract: The paper describes the synthesis and structural characterization of six new diorganotin(IV) compounds 1–6, [R2SnL] and a monoorganotin(IV) derivative, C4H9SnClL (7). Here L = N′-(5-bromo-2-oxidobenzylidene)-N-(oxidomethylene)hydrazine ligand with ONO tridentate chelation capability and R = CH3 (1), C2H5 (2), n-C4H9 (3), C6H5 (4), C8H17 (5), tert-C4H9 (6), The packing diagram offers a supramolecular structure for 1 and a dimeric structure for 4 with distorted square-pyramidal and distorted trigonal geometry, respectively. The different geometry of 1 than 4 can be attributed to the presence of intermolecular non-covalent Sn---O and Sn---H interactions in the former. The antifungal, antibacterial, antiurease and antileishmanial activities of these complexes proved them to be active biologically and may be formulated as new metal-based drugs in future. [Copyright &y& Elsevier]

Abstract: This article describes the synthesis of triorganotin(IV)-, chlorodiorganotin(IV)- and diorganotin(IV) 4-ethoxycarbonylpiperazine-1-carbodithioates with general R3SnL {where R=CH3 (1), n-C4H9 (2) and C6H5 (3)}, R2SnClL {where R=CH3 (4), n-C4H9 (5) and C6H5 (6)} and R2SnL2 {where R=CH3 (7), n-C4H9 (8) and C6H5 (9)}, respectively. The coordination behavior of ligand (L) in all compounds was investigated by different analytical techniques such as FT-IR and multinuclear NMR. X-ray single crystal analysis confirmed supramolecular structure for compounds (3) and (4) with distorted trigonal-bipyramidal and distorted square-pyramidal geometries, respectively. The compounds have pronounced antimicrobial (antibacterial and antifungal) potency and moderate insecticidal activity. These compounds also inhibit effectively the activity of urease enzyme. [Copyright &y& Elsevier]

Abstract: Metallacyclic palladium(II) complexes [Pd(L)(R3P)Cl], L=TIQDTC (1,2,3,4-tetrahydroisoquinolinedithiocarbamate), 4MpipDTC (4-methylpipradinedithiocarbamate), MPizDTC (N-methylpiperazinedithiocarbamate), R3P=Ph3P, (o-tolyl)3P, Ph2ClP, were synthesized in a 1:1 molar metal–ligand ratio. These complexes were characterized by elemental analyses, FT-IR, multinuclear (1H, 13C and 31P) NMR. The X-ray crystal structures of [Pd(TIQDTC)(Ph3P)Cl] and [Pd(TIQDTC)((o-tolyl)3P)Cl] show a slightly distorted square planar environment around the Pd(II) ion with S–Pd–S and P–Pd–Cl average bond angles of 74.51 and 92.41, respectively. These complexes were screened for cytotoxic, antifungal, anti-inflammatory and antibacterial activity. Some complexes exhibit a significant activity against fungi. [Copyright &y& Elsevier]

Abstract: Four new organotin(IV) carboxylates, [Bu2SnL2] (1), [Et2SnL2] (2), [Bu3SnL] n (3), [Me3SnL] n (4), where L=4-nitrophenylethanoates, were synthesized and characterized by elemental analysis, FT-IR and multinuclear NMR (1H and 13C). Spectroscopic results authenticated the coordination of ligand to the organotin moiety via COO group while X-ray single crystal analysis revealed bidentate chelating mode of coordination of ligand in complex 2 and a bridging behavior in complexes 3 and 4. Cyclic voltammetric (CV) technique was used to evaluate the electrochemical, kinetic and thermodynamic parameters of complexes 1-4, interacting with DNA. The linearity of the plots between the peak current (I) and the square root of the scan rate (ν 1/2) indicated the electrochemical processes to be diffusion controlled. The diffusion coefficients of the free (D f) and DNA bound forms (D b), standard rate constants (ks) and charge transfer coefficients (α) were determined by the application of Randle–Sevcik, Nicholson and Kochi equations. Furthermore, the binding constants evaluated from voltammetric data revealed the following increasing order of binding strength: 2 < 1 < 4 < 3. For 1 and 2, the activity against prostate cancer cell lines (PC-3) was found consistent with the order obtained from voltammetric behavior. [Copyright &y& Elsevier]

Abstract: Two chlorodiorganotin(IV) complexes with general formula R2SnClL (R= n-C4H9 (1) and C2H5 (2) and a diphenyltin(IV) derivative with general formula Ph2SnL2 (3), where L=4-(4-nitrophenyl)piperazine-1-carbodithioate ligand, were prepared and characterized by elemental analysis, Raman, FT-IR, multinuclear NMR (1H, 13C and 119Sn) and mass spectrometry. On the basis of spectroscopic data the effective coordination number of Sn atom was found five (1 and 2) and six (3) both in solution and solid state. Electrochemical, kinetic and thermodynamic parameters of complexes 1–3, interacting with DNA were evaluated by cyclic voltammetry. The linearity of the plots between the peak current (I) and the square root of the scan rate (ν 1/2) indicated the electrochemical processes to be diffusion controlled. The diffusion coefficients of the free (D f) and DNA bound forms (D b), standard rate constants (ks) and charge transfer coefficients (α) were determined by the application of Randle–Sevcik, Nicholson and Kochi equations. The values of binding constant and binding site size were evaluated from voltammetric data. The results revealed the following increasing order of binding strength: 1 (5.4×103)< 3 (8.4×103)< 2 (1.24×104)M−1. The UV–Vis spectroscopic data also indicated the same order of binding strength. Furthermore, the binding mode was suggested on the base of shift in peak potential (CV) and absorption maxima (UV–Vis spectroscopy). [Copyright &y& Elsevier]

Alkyn-1-yl(methyl)silanes Me2(H)Si–C&z.tbnd6;C–R (1), Me(H)(Cl)Si–C&z.tbnd6;C–R (2) and Me2(Cl)Si–C&z.tbnd6;C–R (3) [R=Bu (a), tBu (b), Ph (c), SiMe3 (d)] react with 9-borabicyclo[3.3.1]nonane (9-BBN) by 1,2-cis-hydroboration to give selectively (except of 3d) the alkenylsilanes 4 (from 1), 5 (from 2), and 6 (from 3), in which the boryl group has become attached to the carbon atom adjacent to the silyl group bearing functional substituents. In the case of 3d, a mixture consisting of the alkenes 6d and the isomers 7d, 8d and 9d is obtained. All products were characterised by NMR spectra (1H-, 11B-, 13C- and 29Si-NMR) in solution, and in the cases of 5c and 6c, the molecular structures in the solid state were determined by X-ray analysis. [Copyright &y& Elsevier]

1-Sila-2,4-cyclopentadienes (siloles) bearing five organyl groups and a diethylboryl group in 3-position (3), four organyl groups, a trimethylstannyl and a diethylboryl group in 2,4-positions (4), four organyl groups, a diethylboryl group in 3-position and a hydrido function at the silicon atom (5) react by [4+2]cycloaddition with dimethyl acetylenedicarboxylate, MeOC(O)&z.sbnd;C&z.tbnd6;C&z.sbnd;C(O)OMe (1), and tetracycanoethylene, (NC)2C&z.dbnd6;C(CN)2 (2), to give 7-silanorbornadienes (6–8) and 7-silanorbornenes (10–12), respectively. The silole 5 is converted into isomers 8 and 8′, and 12 and 12′, in which the SiMe group in each major isomer (8 and 12) occupies the syn-position with respect to the C(2)&z.dbnd6;C(3) bond. The molecular structure of 10a was determined by X-ray analysis. The 7-silanorbornadiene (7) rearranges into a benzene derivative by formation of an Si&z.sbnd;O bond and 1,3-migration of the trimethylstannyl group. All products were characterised in solution by multinuclear magnetic resonance (1H-, 11B-, 13C-, 29Si-, 119Sn-NMR spectroscopy). The geometries of 1,4,7,7-tetramethyl-7-silanorbornadiene, -7-silanobornene, and -7-silanorbornane were optimised by ab initio MO calculations (RHF/6-311+G(d,p) and chemical shifts δ29Si were calculated (GIAO-RHF/6-311+G(d,p)). [Copyright &y& Elsevier]

Exchange reactions of spirocyclic stannoles with boron, tin and phosphorus halides lead to stannoles 4, 5 and 6, 7, in which the tin atoms bear two chloro or two bromo ligands. The same stannoles 4 and 5 were prepared by 1,1-ethylboration of bis(trimethylsilylethynyl)tin dichloride (8) or -dibromide (9), prepared in situ from tetrakis(trimethylsilylethynyl)tin and tin tetrachlodide or -tetrabromide. Alkenes with a similar pattern of substituents at the C&z.dbnd6;C bond were prepared either by 1,1-ethylboration of the trimethylsilylethynyltin trihalides (10, 11, leading to 12, 13) or by exchange reactions of organotin substituted alkenes with tin tetrachloride (leading to 14). All compounds, in which a trimethylsilyl and an SnX2 moiety (in the stannoles 4, 5) or an SnX3 group (in the alkenes 12, 13) are in geminal positions at the olefinic carbon atoms, decompose already at room temperature by elimination of SnX2 (X=Cl, Br). Exceptionally small coupling constants ∣1J(119Sn, 13C)∣ are observed for these compounds. The comparable derivatives, in which the trimethylsilyl groups are replaced by propyl (stannoles 6, 7, and the alkene 14), are much more stable, and the magnitude of ∣1J(119Sn, 13C)∣ is found in the expected range. [Copyright &y& Elsevier]